Field of the Invention
The present invention relates to a piezoelectric material, in particular, a lead-free piezoelectric material. The present invention also relates to a piezoelectric element, a multilayered piezoelectric element, a liquid discharge head, a liquid discharge device, an ultrasonic motor, an optical apparatus, a vibratory device, a dust removing device, an image pickup device, and an electronic apparatus including the piezoelectric material.
Description of the Related Art
Piezoelectric materials are generally ABO3 perovskite-type metal oxides such as lead zirconate titanate (hereinafter referred to as “PZT”). However, since PZT contains lead as an A site element, its influence on environment is controversial. Accordingly, there is a demand for a piezoelectric material of a lead-free perovskite-type metal oxide.
Barium titanate is known as a piezoelectric material of a lead-free perovskite-type metal oxide. In addition, in order to improve the characteristics, a material of which base composition is barium titanate has been developed.
Japanese Patent Laid-Open No. 2009-215111 discloses a piezoelectric material having an improved piezoelectric constant at room temperature of barium titanate by replacing a part of the A site of barium titanate with Ca and a part of the B site with Zr. Japanese Patent Laid-Open No. 2010-120835 discloses a piezoelectric material having an improved mechanical quality factor at room temperature of barium titanate by adding Mn, Fe, or Cu to a material obtained by replacing a part of the A site of barium titanate with Ca.
However, piezoelectric materials of known technology have problems that the piezoelectric constant is low in a high temperature region of a device driving temperature range (−30° C. to 50° C.), whereas the mechanical quality factor is low in a low temperature region. The present invention has been made in order to solve the above-mentioned problems and provides a lead-free piezoelectric material having satisfactory piezoelectric constant and mechanical quality factor in a device driving temperature range.
The present invention also provides a piezoelectric element, a multilayered piezoelectric element, a liquid discharge device, an ultrasonic motor, an optical apparatus, a vibratory device, a dust removing device, an image pickup device, and an electronic apparatus including the piezoelectric material.